A91Billable, valid for claims from October 1, 2026

Dengue hemorrhagic fever

In Arthropod-borne viral fevers and viral hemorrhagic fevers (A90-A99), chapter 1: Certain Infectious and Parasitic Diseases

  • A91 is billable and valid on claims for FY 2027. If the record has more detail, check the other codes under A90-A99 below.
  • As a secondary diagnosis it is a CC (complication or comorbidity), which can raise the MS-DRG payment. It doesn't count when the principal diagnosis is one of 23 closely related codes.
  • Doesn't count toward a Medicare Advantage risk score (no HCC in V28).
  • AHRQ's Chronic Condition Indicator classes it as not chronic (an acute or short-term condition).

Also indexed as: Bangkok hemorrhagic fever; Dengue, hemorrhagic; Fever, Bangkok hemorrhagic; Fever, dengue, hemorrhagic; Fever, hemorrhagic NOS, Bangkok; Fever, hemorrhagic NOS, dengue; Fever, hemorrhagic NOS, Philippine; Fever, hemorrhagic NOS, Singapore; Fever, hemorrhagic NOS, Southeast Asia; Fever, hemorrhagic NOS, Thailand; Fever, Philippine hemorrhagic; Fever, Singapore hemorrhagic; Fever, Southeast Asia hemorrhagic; Fever, Thailand hemorrhagic; Singapore hemorrhagic fever; Southeast Asian hemorrhagic fever; Thailand hemorrhagic fever

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Official coding guidelines

From the ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027 (CMS and NCHS). Links open the PDF at the right page.

Rules for coding infections and parasitic diseases, including HIV, organism and drug resistance codes, sepsis and septic shock, MRSA, Zika, and COVID-19.

Read Section I.C.1 (page 19)

A91 MS-DRGs

As the principal diagnosis, A91 groups to MS-DRG 865 or 866 (v44.0). Which one applies depends on procedures performed, secondary diagnoses (CC/MCC), and the patient's age and discharge status.

Related conditions

Grouped by AHRQ's Clinical Classifications Software Refined (CCSR), which sorts every diagnosis code into clinically meaningful categories.

A91 is in Viral infection (INF008, its default category), with 309 codes. Others in it:

  • A08.0 Rotaviral enteritis
  • A08.11 Acute gastroenteropathy due to Norwalk agent
  • A08.19 Acute gastroenteropathy due to other small round viruses
  • A08.2 Adenoviral enteritis
  • A08.31 Calicivirus enteritis
  • A08.32 Astrovirus enteritis
  • A08.39 Other viral enteritis
  • A08.4 Viral intestinal infection, unspecified

Other codes that refer to A91

Notes on these codes point to A91.

  • A90 Excludes1: dengue hemorrhagic fever (A91)
  • A98 Excludes1: dengue hemorrhagic fever (A91)

About the condition

Plain-language background from MedlinePlus (National Library of Medicine), not coding guidance.

Dengue

Dengue is a viral infection. It can be caused by four related viruses. You can get it if an infected mosquito bites you. It is common in warm, wet areas of the world. Although rare, it can be found in some parts of the United States. Outbreaks are more common during rainy seasons.

Read more about dengue on MedlinePlus

Code history

Valid since FY2016, when ICD-10-CM took effect on October 1, 2015. No changes since.

ICD-9-CM equivalent

Legacy crosswalk from the CMS General Equivalence Mappings (last updated 2018).

  • 065.4 Mosquito-borne hemorrhagic fever (approximate)
ICD-9 to ICD-10 converter